Advanced oriented assist features for integrated circuit hole patterns
AssigneeMacronix International Co., Ltd.
InventorChin Yang
Life of this patent
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Abstract
An oriented assist feature is described that permits transferring a lithographic pattern from a to an integrated circuit. The oriented assist feature does not exhibit a forbidden pitch phenomenon, thereby providing a wide photo process window for a hole pattern.
Claims24
A method of optically transferring a lithographic pattern corresponding to an integrated circuit from a mask onto a semiconductor substrate by use of an optical exposure tool, the method comprising:
- forming a plurality of main features on the mask, the features corresponding to elements on the integrated circuit;
- and
- forming a plurality of oriented assist features on the mask disposed near the plurality of main features, the plurality of assist features having a length dimension and a width dimension, the length dimension being greater than the width dimension, the length dimension further being oriented in a direction nominally outward and perpendicular to edges of the plurality of main features.
A method of forming a mask for optically transferring a lithographic pattern having a plurality of isolated elements onto a semiconductor substrate, wherein spacing between isolated elements is controlled according to a given pitch, the method comprising:
- disposing a plurality of assist features around the plurality of isolated elements, each assist feature having a width, a length, a first separation parameter defining a distance between individual assist features, and a second separation parameter defining a distance between the plurality of assist features and the plurality of isolated elements;
- determining optimized values of the width, the length, the first separation parameter, and the second separation parameter;
- and
- setting an assist feature rule according to the given pitch and the optimized values.
Dependencies are inferred from the claim text.